This paper develops and tests a comprehensive psychological model of how narrative messages persuade. In this model, perceived realism and perceived similarity are considered as the antecedents of narrative engagement variables. There are three forms of narrative engagement, transportation, identification, and parasocial interaction, which are conceptualized as the primary mediating mechanisms. Message elaboration and psychological reactance are proposed as the secondary mediating mechanisms. A web-based study (N = 374) was conducted to test this complex model. Four video clips on sexual health topics from wellknown television series were used as the stimuli. Structural Equation Modeling (SEM) analyses showed that perceived realism and perceived similarity were antecedents of narrative engagement. There was conceptual overlap between the narrative engagement variables, but they remained distinct from each other. There was no unique effect on persuasion from parasocial interaction. There was evidence for direct effects on persuasion from transportation and identification, as well as their indirect effects through reducing psychological reactance. However, message elaboration was found to be negatively associated with message perception. Implications for narrative communication in general and future studies were discussed.